1. Technical Field
This invention relates to seat belt usage indicating systems, and more particularly to such a system that monitors rear seating rows of a vehicle for the presence of passengers and generates an alert if a passenger restraint system in the rear seating rows is not properly used.
2. Background Art
Modern automotive vehicles generally include seat belt usage indicating systems for occupants of the front row seating positions of the vehicle. These systems are intended to provide a reminder to the front seat occupants if they fail to properly fasten their seat belts when the vehicle is in operation.
As the safety advantage of restraint belt use by all vehicle occupants has been recognized, it has been proposed to extend seat belt usage monitoring to the rear seating rows so that vehicle occupants (the driver of the vehicle and/or vehicle passengers) may be alerted if a passenger in a rear seating row is not using his or her restraint belt.
Since such an alert is only appropriate and useful when a seat in the rear row is actually occupied, some way must be provided to detect the presence of a passenger in a particular seat. Many different types of seat occupancy sensors have been proposed. These include pressure-sensing bladders or load-responsive electrical switches installed in the seat, optical devices using scene recognition algorithms, and capacitive sensors. All of these proposed devices add considerable complexity and expense to the vehicle.
In view of the above, it would be advantageous to provide a restraint belt monitoring system for the rear rows that is able to accurately determine occupancy with little or no added cost and complexity.